In fierce fighting that killed more than 200 combatants, Nigerian troops clashed with Islamic extremists who attacked Maiduguri, the biggest city in north-eastern Nigeria, from three fronts.
At the same time the insurgents continued scorched-earth attacks on villages 125 miles to the south in Adamawa state, slitting throats of residents, looting and burning homes and abducting dozens of trapped women and children, according to Vandu Kainu and other escaping survivors.
Adamawa state legislator Adamu Kamale appealed for troops to protect civilians in Michika, where six villages are under attack. "The attacks have continued since Friday with no presence of security operatives," he complained.
The multiple attacks come as US secretary of state John Kerry visited Lagos, Nigeria's commercial capital nearly 1,000 miles south west of Maiduguri, to encourage peaceful elections on February 14 in Africa's most populous country.
"This will be the largest democratic election on the continent," Mr Kerry said. "Given the stakes, it's absolutely critical that these elections be conducted peacefully - that they are credible, transparent and accountable."
Mr Kerry met with President Goodluck Jonathan and his chief rival candidate, former military dictator Muhammadu Buhari. Mr Kerry told reporters afterwards that he won pledges from both to refrain from violence.
He also issued a warning that anyone responsible for inciting post-election mayhem will be barred entry to the United States, where millions of Nigerians live.
Mr Kerry promised more US support in the fight against Boko Haram if the elections take place peacefully and democratically.
More than 800 people were killed in northern protests after Buhari, a Muslim northerner, lost 2011 elections to Mr Jonathan, a Christian from the south.
Boko Haram has denounced democracy and wants to make an Islamic state of Nigeria, whose population of about 170 million is divided almost equally between Muslims in the north and Christians in the south.
In Maiduguri, troops blocked roads into the city, which also prevented civilians from escaping.
A Defence Ministry spokesman said that troops successfully repelled attacks on Maiduguri and Konduga, 25 miles to the south east.
But he said they were mounting air raids in Monduno, a town 88 miles north east of Maiduguri, which Boko Haram seized this morning.
More than 200 combatants died, mainly insurgents, according to soldiers and civilian self-defence fighters who counted bodies.
Mr Jonathan made a surprise visit to Maiduguri 10 days ago and pledged to crush the insurgents. But his repeated promises are ringing hollow as Boko Haram since August has seized and kept control of large swaths of the north east, including key border crossings into Cameroon, Chad and Niger.